1. Field of the Invention
The present invention relates to a multilayer ceramic capacitor, a multilayer ceramic capacitor series including the same, and a multilayer ceramic capacitor mount body including the same.
2. Description of the Related Art
An example of the related art that discloses a multilayer ceramic capacitor in which the occurrence of cracks may be suppressed is Japanese Unexamined Patent Application Publication No. 2012-248581. In the multilayer ceramic capacitor disclosed in this publication, a base unit includes an inner electrode body (inner layer portion) and first and second dielectric bodies (outer layer portions). The inner electrode body is constituted by first inner electrodes and second inner electrodes facing each other with a dielectric member therebetween and stacked on each other. The first and second dielectric bodies sandwich the inner electrode body therebetween in the stacking direction. The first dielectric body including a first main surface of the base unit is thicker than the second dielectric body including a second main surface of the base unit in the stacking direction.
One of the reasons why cracks occur is as follows. When a substrate having a multilayer ceramic capacitor mounted thereon is deflected due to an external force, an external stress is produced. This external stress acts on a dielectric layer of the multilayer ceramic capacitor, which causes the occurrence of cracks. The present inventors have discovered another reason why cracks occur. When a multilayer ceramic capacitor is subjected to firing, an internal stress is produced due to the difference in the coefficient of thermal contraction between dielectric layers and conductive layers. This internal stress acts on the boundary between the inner layer portion and the outer layer portion, thereby causing the occurrence of cracks (delamination).
In the multilayer ceramic capacitor disclosed in the above-described publication, the occurrence of cracks caused by an external stress may be suppressed, but the occurrence of cracks caused by an internal stress produced by the difference in the coefficient of thermal contraction between dielectric layers and conductive layers is not considered.